Implement GDScript mod loading

[hhyyrylainen]

From some investigation it seems that gdscript mods can't start executing by themselves, we need to add a new property in the ModInfo to specify that a scene should be loaded and attached to the root node from a mod. This should allow gdscript made code mods to load.

After this works an example mod should be made: Revolutionary-Games/ThriveMods#5
and instructions updated: https://wiki.revolutionarygamesstudio.com/index.php?title=Modding

[I-Have-No-Idea-What-IAmDoing]

Could gdscript mods start execution the same as c# mod by calling a initialize function?

[hhyyrylainen]

How do you instantiate a gdscript class, then? I don't know how that would work, that's why I suggested the approach of attaching a basically an "autoload" from the mod to the Scene tree, then the ready method in the gdscript file for that scene can run.

[I-Have-No-Idea-What-IAmDoing]

to create the script you have load it using the ResourceLoader as a 'GDScript' and then use the '.new()' function to create a new instance of the script and then you can call the intilize function using the '.call()' function

docs you can view:

• https://docs.godotengine.org/en/stable/getting_started/scripting/cross_language_scripting.html#calling-gdscript-methods-from-c
• https://docs.godotengine.org/en/stable/getting_started/scripting/cross_language_scripting.html#instantiating-gdscript-nodes-from-c
• https://docs.godotengine.org/en/stable/classes/class_gdscript.html

this is the way i did it in my personal modloader, though only GdScript worked:

            // Entry Script Loading
            if (currentMod.EntryScriptPath != null && ResourceLoader.Exists(currentMod.EntryScriptPath))
            {
                var entryScript = ResourceLoader.Load(currentMod.EntryScriptPath) as Script;

                Object entryScriptInstance = new Object();

                if (entryScript?.CanInstance() == true)
                {
                    // Need to create an instance of the resource create a object of the class
                    switch (Path.GetExtension(ProjectSettings.GlobalizePath(currentMod.EntryScriptPath)))
                    {
                        case ".gd":
                            var gdEntryScript = entryScript as GDScript;
                            entryScriptInstance = (Object)gdEntryScript?.New();
                            break;
                        case ".csx":
                        case ".cs":
                            var cSharpEntryScript = entryScript as CSharpScript;
                            entryScriptInstance = (Object)cSharpEntryScript?.New();
                            break;
                        case ".c":
                        case ".cpp":
                        case ".cc":
                        case ".cxx":
                            var nativeScriptEntryScript = entryScript as NativeScript;
                            entryScriptInstance = (Object)nativeScriptEntryScript?.New();
                            break;
                    }

                    // Calls the intialization method, passing in the ModInfo, so that mods can get their own config
                    entryScriptInstance?.Call(currentMod.EntryFunctionName, currentMod);
                }
            }

[hhyyrylainen]

That's a pretty interesting approach.
Is there a concrete benefit of having it be like that versus just needing a Node where the ready loads the mod? I think many mods that contain code will want to attach at least one Node to the scene tree so that would save one step from the mod author.

[I-Have-No-Idea-What-IAmDoing]

probably not beside making everything work the same